1. Field of the Invention:
The present invention relates generally to improvements in impact absorbers and more particularly to an impact absorber utilizing a damping liquid for an automobile bumper.
2. Description of the Prior Art:
An impact absorber including outer and inner tubes and a rod member, such as a piston rod, arranged within the inner tube to which an impact force is directly inflicted is already known to the prior art. In this type of impact absorber, torsion between the inner tube and the rod member is brought out when an impact force acts on the impact absorber at an angle with respect to the axis thereof. Since the inner tube does not slide smoothly into the outer tube, the original function of the impact absorber is not satisfactorily achieved. Another type of impact absorber in which an inner tube serves for the rod member and a plurality of variable orifices are formed through an outer tube in order to improve the efficiency of absorption is also already known to the prior art. In this type of impact absorber, since a plurality of variable orifices are formed through the outer tube, the manufacturing of the outer tube is very difficult. Furthermore, in order to strengthen the outer tube, the dimension of the external form thereof must be enlarged.